Im getting a new iPhone 4 during this week, and that means that i don't got any more open slots in my App Store account/ Apple ID, right? (its activated on 3 other devices.) How do i inactivate the account on just one iPhone? Restore the device?
That's for desktop iTunes, not iDevices.
^ yes. It's your computers that are authorized.
So theoretically could let the whole town share the same account oct their iPhones?
(But yep, unlimited iOS devices.)